Final answer:
The true opportunity cost of going to college, amongst the provided options, is the job you would have taken if you opted not to attend school, as opportunity cost encompasses the value of the next best alternative forgone, which in this scenario is the loss of potential earnings.
Step-by-step explanation:
The opportunity costs of going to college include not just the direct expenses such as tuition and books, but also the cost associated with alternatives you give up by choosing to attend college. In this case, items (a) and (b), tuition and books, are the monetary costs or out-of-pocket costs.
However, the opportunity cost is best represented by item (c), the job you were going to take if you did not go to school. This is because opportunity cost refers to the value of the next-highest-valued alternative use of that resource; in this case, the earnings you forgo by not working. Therefore, while (a) and (b) are costs of attending college, they are not considered opportunity costs. Item (c) is the true opportunity cost among the options provided.